Parabellum ammo? You must be joking. I thought it's about 14.5mm KPVT or 30mm shells for Shilka
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You rarely need AP ammo to stop an attacker - rarely one will wear a vest/etc. On the other hand - your shot may pierce through the body of the target and hit somebody else.
Ammo and weaponry are just a part of the equation. Laws about usage make a huge difference. "An attorney check is attached to each bullet you shoot" - and even that may not be helpful enough.
In Russia (stop laughing) there are multiple cases when people get jailed for defending themselves/their homes/etc. One guy on youtube told his story where he was defending from several drunk attackers who grabbed him and tried to beat him - he shoot several times "somewhere behind" while wrestling with them (lately he knew he had shoot off a "ball" of one of the guys). The footage from multiple surveillance cameras was available and it clearly showed who has started the "violent" part and what was going on. The attackers didn't file a criminal charge for some reason - so he decided not to do that as well (as he only got scratches/etc while one of the attackers got serious damage). The case came down to "shooting in a place where you're not allowed to shoot" and there's nothing about self-defense in non-criminal cases. Morale? "Don't use weapons for self defense if you're not at the shooting range". Such things are ridiculous till the very moment you get in similar situation. Other guy has prevented a pedophile from "youknowwhat", probably killing him in the process - got 7 years in jail and still says he'd act the same if he had to. Not everyone is prepared to pass a part of his life in jail.